For me this is too cheesy and has nothing in ranked or comp. In a pubs game you can do whatever I guess even give kill streaks to get free kills you can't defend against for what I am conserned. But problem comes in ranked when a path can escape on a zip then destroy with followers on so perhaps one dies and the rest can't reach him. If you check around the maps, all the unfair rat and cheese places are slowly patched now so it would not make sense making it part of an ultimate.
Right now he has to defend the zip and can claim kills that way, more fair if you ask me